Developing techniques to measure diet in the distant past is extremely important in epidemiologic studies of diet and cancer as the long latent period of the disease defines a very broad time range during which etiologically important nutritional factors may be acting. We propose a study which is designed to measure the reliability of dietary history as recalled from the past. Three hundred and thirty four 324 individuals who were extensively interviewed regarding their diets between five and eight years ago as part of the Western New York Diet Study will be reinterviewed in this proposed study and asked to recall their usual diet at the time of their original interview. Both the original interview and the reinterview will measure dietary history using the food frequency method, which is the most reasonable method for measuring diet from the distant past. Reliability of the recalled dietary histories will be estimated by direct comparison with the diet histories as originally measured five to eight years ago. Current diet will also be ascertained in the interview. This will allow us to quantify dietary changes over time as well as to measure any possible bias that the current diet might introduce into recalled past diet. The spouse of each study subject will also be interviewed regarding the subject's past diet in order to obtain an additional measure of past diet. This will be useful to test the reliability of a single measure of past diet by a surrogate respondent, as well as to test the improvement in accuracy of recall when two independent estimates of past diet are combined for the spouse pair to generate a single joint estimate.